My Experience - 2X Teleconverter

In the pass I was educated by some articles that only the object-lens possess the "resolution", anything behind the lens cannot increase the resolving power of the lens. I was believed that the 2X converter will decrease the prime lens resolution by 50%, so I rare use teleconverter.

I had changed my mind after I had read an article from "Popular Photography" Feb. 97 issue, it was talked about teleconverters. Which shown some pictures taken by a Nikon 35-105mm/F3.5-4.5 zoom used with 4-element and 7-element 2x converters, they were compared with the same manufacturer's 70-210mm/F4-5.6 zoom. The result shown that the 7-element teleconverters plus the 35-105 zoom gave comparable results to the 70-210 zoom and the 4-element teleconverter only got a shade softer.

The article also pointed out that some very old 4-element teleconverter have very poor quality, it was the case I had. I had a 4-element Tamron F OM teleconverter, the quality was poor when used with many of my OM lenses. After I read the article, I go out and search for the Olymplus 2X-A teleconverter. After a month trial, I was lucky that I found one. Of my eight years and hundreds of visit to the second-hand camera shops, this was the second time I saw the 2X-A converter. The fist time was a 85% new 2X-A cost HKD700, this time it was a 99% new but cost HKD1900, I thought it was too expensive. Later I found a 7-element Tamron 2X SP F at HKD300 and I bought it.

After making a few test shoots of this teleconverter with my 100mm/F2 lens and 50mm/F1.4 lens, I found the result was excellent. With the 100mm/F2 at F2, the picture quality was comparable to my Zuiko 200mm/F4 and with the 50mm/F1.4 it was very good when set to F2.8. One problem of this teleconverter is the high field curvature, when focus at the middle, both edges will be a little bit out of focus. This will affect picture quality when shooting a flat object with large aperture lenses wide open, but for shooting portrait or macro, you may never notice this.

Recently I have got an OM 2X-A from an OM outfit, it is very nice and the preliminary test result shown that it works very well with the 200/4. I will post more information later when I have more experience with it. The problem with the 2X-A is it only fit a limited number of primes.

(Updated on: 19-May-99)